Lecture 5

Question 1

Inheritance patterns (4)

Answer 1

Autosomal dominant (e.g. Huntington’s disease)

Autosomal recessive (e.g. cystic fibrosis)

X-linked recessive (e.g. Duchenne muscular dystrophy)

Mitochondrial

Question 2

Genetic markers in linkage analysis (3, in order of descending size/increasing current usefulness)

Answer 2

Restriction fragment length polymorphisms (RFLPs), microsatellites, single nucleotide polymorphisms (SNPs)

Question 3

How is mutation relevant to linkage analysis?

Answer 3

Mutation may occur at site of restriction enzyme (in a palindrome) => no cut at side => different banding pattern in post-electrophoresis Southern blot

Question 4

Unit of measure in linkage analysis

Answer 4

centiMorgan (1cM = 1 million bp); distance between markers derived from frequency of separation during crossing over

Question 5

Uses of polymorphisms (4)

Answer 5

Paternity testing, criminal identification, localization of genes (e.g. autosomal dominant high myopia on chromosome 17), genome wide association studies (GWAS; extension of old-time localization)

Question 6

DNA sequencing, the Frederick Sanger way (3 details)

Answer 6

Small amount of ddNTPs applied with normal dNTPs to stop replication at successive base pairs in resulting DNA molecules

ddNTPs have different tags for different bases (A,T,C,G)

Resulting DNA molecules run through polyacrylimide gel electrophoresis; different molecule lengths with tags will show order of base pairs

Question 7

Polymerase chain reaction recipe

Answer 7

Start with a bath of nucleotides and polymerase. Add the DNA molecule to be amplified, and heat to break hydrogen bonds. Allow RNA primers to bind, then allow the polymerases to create new DNA molecules. Cycle the heating as many times as desired.

Question 8

Ingredients for polymerase chain reaction

Answer 8

DNA template to amplify
DNA polymerase (Taq used in Marrs lab)
dNTPs
RNA primers complimentary to 3’ end of both DNA strands